By on March 25, 2014

images

Motorsports enthusiasts sometimes don’t realize that behind the glamour of car and motorcycle racing we see on television there is an extensive support industry that makes everything from specialized dipsticks to complete racecars. Much of that industry is located in three locations around the globe. England’s so called Motorsports Valley is where 8 of the 11 F1 teams have their race shops within about an hour’s drive from the Silverstone track, in  Northamptonshire, Oxfordshire and the South Midlands. About 45,000 people in the UK make their living from motorsports. In the U.S., the racing industry is primarily centered, not surprisingly, around Indianapolis, Indiana and Charlotte, North Carolina, home of the Indianapolis 500 and NASCAR, respectively. It should also come as no surprise that Indiana’s Purdue University and the University of North Carolina at Charlotte have both examined the economic impact of motorsports in their states. Purdue reports that more than 23,000 people are employed directly by the motorsports industry in Indiana which in turn are responsible for another 423,000 indirect jobs. A decade ago UNC Charlotte found that motorsports then contributed $5 billion to the North Carolina economy.

560_mfr

Every year in December there is a big two day trade show in Indianapolis that was originally put on by Performance Racing Industry magazine. The PRI show, which draws thousands of racing professionals and is not open to the public, is now owned by the promoters of the SEMA show in Vegas. Dave Szerlag, who owns D&M Motorsport Promotions in Brighton, Michigan, and his business associate Luke Bogacki, realized that Indy and Charlotte aren’t the only areas in the country that have a critical mass of companies devoted to performance and racing cars, so they decided to organize the first Motor City Hot Rod & Racing Expo, held outside Detroit in Novi. Based on the fact that 140 vendors, from Michigan and around the country, bought up all 65,000 square feet of available display space, and the fact that every vendor that I spoke to said they were happy with the business they did at the show, I’d say that the inaugural event was as success. Szerlag and Bogacki told me they’re already planning next year’s show.

710001_lg

One of those vendors was J&J Performance of Shreve, Ohio and the main reason why I stopped by their booth was because the words “Engine Diapers” on their sign caught my eye. When a drag racing engine breaks, the term “grenading” is appropriate. Hard metal parts start flying and connecting rods or other components will simply break holes into the side of the crankcase or down through the sump as they continue on their vectors.

Why they call it a "thrown" rod.

Why they call it a “thrown” rod.

Considering the kind of damage that can happen when the engine in a production street car throws a rod, you can imagine how violent it is when a racing engine putting out more than a thousand horsepower (and in the case of top fuel engines running on nitromethane, several thousand horsepower) starts to break. That creates a safety problem since those flying parts can be in the proximity of the driver and the leaking oil can cause a fire or create traction problems for both drag racing competitors. It also annoys track owners when drag racers’ engine parts and oil get dumped on their tracks. Hence ballistic engine diapers are now being required by the NHRA and IHRA for some racing classes.

When a top fuel engine blows up, it really blows up.

When a top fuel engine blows up, it really blows up.

J&J is one of a number of firms that make engine diapers. The name is appropriate as an engine diaper wraps around the engine’s bottom end, keeping any leaking oil or stray parts contained. The diaper is secured to the engine with straps, not safety pins (nor for you modern parents who don’t know how to use cloth diapers, adhesive strips). J&J offers two styles, one of woven Kevlar aramid fabric and the other made of an outer skin of ballistic nylon with an inner core of thin ballistic armor. Other companies make similar soft sided engine diapers as well as more rigid units fabricated with carbon fiber. J&J’s rep told me that the styles are about equally effective and end up weighing about the same, so it’s really more of a personal preference thing.

Back when Formula One allowed purpose-built qualifying engines, some folks called them “hand-grenades”, built to put out massive amounts of power for a limited number of laps. Drag racing engines only need to last 1/4 mile, so they tend to be built very close to the edge of the performance envelope. At the highest echelons of drag racing, the engines are rebuilt after after run. Drag racing in particular is going to experience more blown engines than other kinds of racing, so it’s understandable that the drag racing community has embraced the idea of engine diapers. I’m just surprised that they haven’t caught on in other forms of car racing. One driver’s blown engine in a NASCAR race often leads to yellow flags, so the oil on the track can be cleaned up, if they’re lucky and that oil hasn’t already caused other drivers to spin. Many top level racing series mandate safety items like tethered wheels to reduce the chance of flying debris causing an accident. More widespread use of engine diapers in other forms of motorsports could mean safer racing for drivers and more exciting racing for fans, who don’t pay money to watch fast cars parade around the track behind the pace car.

Ronnie Schreiber edits Cars In Depth, a realistic perspective on cars & car culture and the original 3D car site. If you found this post worthwhile, you can get a parallax view at Cars In Depth. If the 3D thing freaks you out, don’t worry, all the photo and video players in use at the site have mono options. Thanks for reading – RJS

Get the latest TTAC e-Newsletter!

21 Comments on “Drag Racing Depends & Powertrain Pampers: Ballistic Engine Diapers...”


  • avatar
    Mural

    And those flying parts don’t go right through the diaper?

    • 0 avatar
      TonyJZX

      it doesnt say in the article but you can guess they use kevlar composites or other materials normally found in bullet resistant vests and vehicle armor

      if they can resist shells in the range of 3,000ft per sec i think a few flying engines parts arent an issue

      • 0 avatar

        From the post:

        “J&J offers two styles, one of woven Kevlar aramid fabric and the other made of an outer skin of ballistic nylon with an inner core of thin ballistic armor. Other companies make similar soft sided engine diapers as well as more rigid units fabricated with carbon fiber. “

  • avatar
    Toad

    Neat stuff, Ronnie. I learn something from every article.

    ” UNC Charlotte found that motorsports then contributed $5 billion to the North Carolina economy.”

    NASCAR is a big economic contributor to the economy, and the race team HQ’s are very impressive (I drive by Joe Gibbs Racing weekly).

    But take the 5 billion figure with a grain of salt. If you buy a cheeseburger UNC Charlotte’s economics department will claim it had a $10,000 economic impact and indirectly created three full time jobs. They are notorious for producing studies that tout huge economic impacts (or multipliers) for any group that wants government funds.

    • 0 avatar
      05lgt

      All the claims of “impact” and “multipliers” always strike me as purest essence of BS. Claiming that one point in the flow of value is the “origin” and responsible always requires not viewing the sources of thier income as the “source”. Nascar’s income is clearly claimable by television advertising, the advertising is claimable by the various advertising industries, they all have paying customers too. It’s just fluf and I really wish it would get laughed off the podium every time it’s brought up.

      • 0 avatar

        I’m also skeptical of “economic impact” assessments, particularly as they relate to the fiscal benefit of public financing of sports arenas and stadia, but other than employment numbers and gross revenue, how else can we gauge the size of an industry?

      • 0 avatar

        > All the claims of “impact” and “multipliers” always strike me as purest essence of BS. Claiming that one point in the flow of value is the “origin” and responsible always requires not viewing the sources of thier income as the “source”.

        There simply exists some sort of dependency graph among the players. Such structures can be weighted for level of dependence: http://en.wikipedia.org/wiki/Graph_%28mathematics%29#Weighted_graph

        The aggregate size/magnitude of any “industry” or whatever definition is trivial traversal of the structure.

        Whether this is done correctly is another matter.

      • 0 avatar
        CRConrad

        @05lgt: “Claiming that one point in the flow of value is the “origin” and responsible always requires not viewing the sources of thier income as the “source”.”

        Well, from the perspective of analyzing the already-existant status quo, perhaps.

        But if you are going to pump a bunch of money into the economy, the “source” is obviusly the point where you pump it in, and the effects from there on are measurable and (provided a few other coefficients have been measured or calculated before) calculable.

  • avatar
    raph

    Oh yeah, top fuel engines can certainly fail with spectacular results. I remember reading about one engine blowing and a piston being found nearly a mile from the track only because it was lodged in somebody’s windshield.

  • avatar

    It is estimated that AA Fuel and top funny cars are producing about 1000 hp per cylinder from their gigantic V-8 engines!!! HP is estimated because available dynometers aren’t strong enough to handle them.

  • avatar
    danio3834

    Ballistic engine diapers and transmission scatter shields are great technology. They’ve saved at least the limbs of a few guys a know when things let go. Years ago the TH400 trans in my uncle’s Top Sportsman car grenaded into it’s scatter shield with such force that it dented the sheet metal floor. Thanks to the shield, no parts got through. Once taken apart, the transmission case had a giant shark bite out of the middle of the case and not many parts left inside.

  • avatar
    bills79jeep

    If you have any doubts on the utility of these things, check out Don Garlits and his foot.

  • avatar
    CraigB

    As an announcer/lackey at a small dragstrip I’ve seen what diapers can and can’t do.

    Supercharged cars sometimes break the snout off of the crank causing oil to come out above the diaper. A belly pan, a metal pan attached to the frame of the car under the engine, would do a better job in this situation of keeping oil off of the track and out from underneath the tires of the vehicle.

    Another case for diapers is the shrapnel that exits the side of the block can create some havoc. Again we have a supercharged vehicle, in this particular case it was a tube chassis 1955 Chevy sedan delivery, had a rod exit the driver’s side of the block. After it’s exit the rod hits and breaks the steering shaft causing the vehicle to loose steering and send it careening off of the track to take out a light pole 20 feet in the air.

  • avatar
    NeilM

    Well, when your engine takes an unexpected crap, you’ve got to have a diaper.

    Love those photos — talk about ‘exploded view.’

  • avatar
    schmitt trigger

    This diapers must be similar in design to the ones surrounding big airliner jet engines.

    There are plenty of Youtube videos showing catastrophic jet engine failures, which are fully contained within its fairing even though the kinetic energy of a 1 ton rotor spinning 15 to 20,000 RPM must be beyond tremendous.

    Many thanks to Kevlar’s inventors!

  • avatar
    CoreyDL

    Speaking of funny terms, today I called the local building permit office, to ask what needed permits and what didn’t for my home improvements. I started off,

    Me: “I’m going to replace the blacktop driveway, and I don’t have a skirt.”

    Her: “Well if you don’t have – - an apron, you won’t need a permit.”

    Me: “Yes… I meant apron, NOT skirt.”

    Uggh. I laughed afterward, she didn’t.

  • avatar
    Felis Concolor

    Having seen the engine failure which killed an ABC cameraman – live – several decades ago, I quickly came to the conclusion that you can never be too safe in motorsports. That particular accident is why every single Top Fuel engine now requires several ballistic straps to secure the blower (which is what killed the cameraman) and engine block to the vehicle.

    And for those who don’t regularly watch the upper echelons of drag racing, most of the really impressive fireball-type explosions result from transmission failure, which is why numerous pages in the rule books specify the minimum standards required to wrap the transmission and bellhousing with ballistic shields.

  • avatar
    tjh8402

    ” More widespread use of engine diapers in other forms of motorsports could mean safer racing for drivers and more exciting racing for fans, who don’t pay money to watch fast cars parade around the track behind the pace car.”

    off topic thread hijack to rant: Funny, based on the way the Tudor United Sports Car Championship races are being run, I could’ve sworn that was what fans wanted, a nice near 50/50 mix between green flag laps and FCY’s. You might want to go check in with the series officials there Ronnie :-P


Back to TopLeave a Reply

You must be logged in to post a comment.

Subscribe without commenting

Recent Comments

New Car Research

Get a Free Dealer Quote

Staff

  • Contributing Writers

  • Jack Baruth, United States
  • Brendan McAleer, Canada
  • Marcelo De Vasconcellos, Brazil
  • Vojta Dobes, Czech Republic
  • Matthias Gasnier, Australia
  • W. Christian 'Mental' Ward, Abu Dhabi
  • Mark Stevenson, Canada
  • Cameron Aubernon, United States
  • J Emerson, United States